The present invention relates to a method and apparatus for manipulating sheets which form a stream of partially overlapping sheets, and more particularly to improvements in a method and apparatus for confining the sheets of such a stream between successive convolutions of a band which is coiled onto a driven core or the like.
An apparatus which can store the sheets of a stream of partially overlapping sheets (a so-called scalloped stream) between successive convolutions of a first flexible band is disclosed in German Pat. No. 2,207,556. Successive sheets of the stream are delivered to a downwardly moving portion of the running first band which advances toward the driven core whereon the first band is converted into a series of convolutions, i.e., into a portion of a bobbin whose convolutions confine and store the sheets therebetween. A drawback of the patented apparatus (and of the method which can be practiced with such apparatus) is that it necessitates the utilization of a second band which runs with the first band and serves to bias the sheets of the scalloped stream against the descending portion of the first band. This ensures that the sheets cannot leave the first band by inertia, gravity and/or for other reasons. The second band prevents the storing of relatively large numbers of sheets, i.e., such second band imposes limits upon the maximum number of sheets which can be stored between the convolutions of the two bands on the core. Thus, the advantage of having a second band (in order to reduce the likelihood of shifting of the sheets relative to the first band) is achieved at the expense of the capacity of the bobbin, i.e., the bobbin cannot store as many sheets as if the second band were absent.